Fluctuation Theory of Rashba Fermi Gases

TL;DR

This paper develops a fluctuation theory for Rashba Fermi gases with spin-orbit coupling, revealing that beyond-Gaussian effects are crucial and that spin-orbit coupling can significantly increase the superfluid transition temperature.

Contribution

It introduces an approximate non-Gaussian fluctuation theory for Rashba Fermi gases and demonstrates the potential for high transition temperatures due to spin-orbit coupling.

Findings

Beyond-Gaussian effects are essential for accurate physics.

Spin-orbit coupling can boost $T_c$ to near Fermi temperature.

The phase diagram of Rashba Fermi gases is mapped using the new theory.

Abstract

Fermi gases with generalized Rashba spin orbit coupling inducedby a synthetic gauge field have the potential of realizing many interesting states such as rashbon condensates and topological phases. Here we develop a fluctuation theory of such systems and demonstrate that beyond-Gaussian effects are essential to capture the physics of such systems. We obtain their phase diagram by constructing an approximate non-Gaussian theory. We conclusively establish that spin-orbit coupling can enhance the exponentially small transition temperature ($T_c$) of a weakly attracting superfluid to the order of Fermi temperature, paving a pathway towards high $T_c$ superfluids.